Zika virus (ZIKV) is an arbovirus of the genus Flavivirdae. Until recently, infections with were thought to be mild and self-limiting. Since 2015 however, ZIKV infections have been associated with an increase in microcephaly and other birth defects in newborns following infection of the mother during pregnancy. ZIKV also has been associated with Guillain-Barre Syndrome (GBS) in adults. Increasing evidence points to ZIKV as the agent responsible for a variety of birth defects in newborns of mothers who become infected during pregnancy. The relationship of ZIKV infections in pregnant women with adverse outcomes of pregnancy is the subject of ongoing evaluation. Studies to date of infants born to infected women focus on those born with serious birth defects that constitute the congenital Zika syndrome. However, whether there are latent effects on growth and development of infants who are not born with congenital Zika syndrome, and what those effects may be, is presently unknown. Longitudinal studies of infants born to Zika-infected pregnant women therefore are necessary to assess the broader spectrum of possible manifestations of intrauterine or intrapartum Zika exposure, and their natural history. In 2016, NIH initiated a large, multicenter, international observational study of the epidemiology, natural history, and pathogenesis of Zika in infants and pregnancy (the ZIP Study). The ZIP Study follows infants during the first 12 months of life. NIH proposes to study a cohort of Zika exposed children and unexposed control children from the ZIP Study or similar studies beyond infancy into early childhood to evaluate the effects of Zika on child growth and development. This task order addresses NIH's requirement to conduct such a study. maternal health